Abu Dawud Book 2, Hadith Number 1291.
Chapter : Prayer by day.
Narated By Muttalib : The Prophet (PBUH) said: Prayer is to be offered in two rak’ahs; and you should recite the tashahhud at the end of two rak’ahs, and express your distress and humility and raise your hands and say praying: O Allah, O Allah. He who does not do so does not offer a perfect prayer.